Lug strap



April 6, 1943.

H. M. BACON LUG STRAP 2 Sheets-Sheet 2 Filed Oct, 28, 1940 .lEr.

INVE/{TOR v HENRY/7. BACON A TTOR/VE Y5 chinery.

Patented Apr. 6, 1943 LUG STRAP Henry M. Bacon, Dayton, Ohio, assignorThe Dayton Rubber Manufacturing Company,

Dayton, Ohio, a'corporation of Ohio Application October 28, 1940, SerialNo. 363,121

' Claims. "(01. 139-153) My invention relates to improvements in lugstraps used in weaving looms or similar ma- One important object of thisinvention is to provide a lug strap which'is constru'cted'so as topossess improved strength and exhibit greater resistance to wear andfailure by fatigue under the action of heat.

Another object is to devise an improved method of making a lug strapwherein the formation of wrinkles or folds in the laminations or layersforming the U-shaped strap is avoided during manufacture.

Another object is to provide an improved lug strap wherein the strengthand cushion sections are located at the point where it is required togive the greatest resistance to wear or impact strain resulting from thepicker stick action.

These and other objects and advantages will be apparent to those skilledin the art during the course of the following description.

In the drawings:

Figure 1 is a perspective view illustrating the method of fabricating myimproved lug strap by winding the difi'erent layers forming the body ofthe strap on a surface of a drum preparatory to cutting the built-upsleeve body into a strap or plurality of straps of the desired width; I

Figure 2 is a fragmentary sectional view taken through the drum surfaceand laminated sleeve sary to increase the strength and quality ofloom,Lug.

accessories and especially the lug straps. straps of greater strengthare required because the actual picking blow is far greater thanheretofore due to the higher speed at which the looms are operated andthe employing of heavier shut. tles. subsequent shortening of the restperiods, has required that the loom picker possess the property ofsubstantially instantaneously or very rapidly recovering its resiliencyand strength after each pick or blow. Further, due to the increasedspeed of operation, the snap or. harshness of the pick or blow has beenmagnified. resultingin bringing about a greater strain on the pickersticks, which, in turn, has placed an added importance on the cushion orresiliency .of the lug strap.

body forming the body of the'lug strap and taken I substantially alongthe line 22 of Figure 1;

Figure 3 is a vertical sectional view illustrating the use of anexpansible core and means for expanding same for forming the laminatedband comprising a double lug strap into the desired shape whereby thesame can be vulcanized toa tough, durable strap, after which the doublestrap can be severed to form a pair of lug straps; Figure 4 is asectional view taken through a mold showing the built-up sleeve formingthe lug strap body mounted on an expanded core and arranged in a moldcavity for vulcanizing the sleeve into a finished double lug strap;

Figure 5 is a similar sectional view taken through a mold showing amodification wherein an air bag is used for applying pressure to theinner side of the double lug strap during molding and vulcanizing of thesame;

Figures 6 to 11 are sectional views of a lug strap made according tothis invention wherein different laminated constructions are used forforming the lug strap.

In general, the higher speeds and heavier loads of the modern weavinglooms have made it neces- To produce a lug strap having greater strengthand resistance to fatigue and failure under the temperature andoperating conditions of loom machinery, I have found that it isnecessary to 7 construct a lug strap wherein the strength sec- ,tion islocalized at the point of the greatest strength need, which is adjacentthe outside of the strap. All of the power deliveredto the strap is fromthe inside, and, consequently, any materials or fabrication placed onthe outside of the strength section are of little value-for addingstrength to the lug strap. Furthermore, by localizing the strength ortension layer to a very thin area, the compressive forces which set upstrains adjacent the neutral strength axis are reduced to a minimum.

When the strength section of the lugstrap is localized in the outsidelayers of the lug strap the entire remaining body can be made tofunctionas a cushion or resilient portion. This is very importantbecause the cushioning obtained by compression is much better than thatby tension or extension. There is also an added advantage in that a veryrapid recovery of the lug strap to its normal resilient form is obtainedby constructing the lug strap to provide cushioning of the picker blowby compression.

In order to produce a lug strap having the improved strength anduniformly distributed resistance to working stress and properresiliency, it is necessary to eliminate any'possibility of theformation of wrinkles, folds, buckles, or flow strains during thelamination and molding of the lug strap. To this end, each section orlayer forming the lug strap must retain its relative spacing and tensionin the finished strap as in the unfinished stages. This has been theprime The increased speed of operation, with the cause of failure whenthe conventionally made rubber lug straps were changed from a very hardto a softer composition. Wrinkled and buckled portions, always presentin the conventional rub ber lug straps, readily open up with the use ofsofter compositions or materials in the making of the lug strap. It hasalso been found that all the plies of a very hard conventional lug strapwork. as a unit because of the rigidity of the binder holding themtogether. With a softer binder, the buckled inner pliesplace an addedstrain on the outer plies which are already under stress producing aninferior lug strap.

My invention overcomes the defectsmentioned and provides a strong,durable lug strap and a convenient and comparatively inexpensive methodfor manufacturing lug straps in large quantities with the minimumpossibility of producing straps which are not uniform. The inventionalso provides a lug strap of improved structure made of materials whichrender the strap freefrom attack by rodents .and wherein wrinkles,buckles, or folds in the laminated layers forming the lug strap, withtheir resultant detrimental effects, are entirely eliminated and a strapis produced wherein the stress is uniformly distributed throughout thebody of the strap.

Inthemanufacture of lug straps embodying the improved construction, Ihave built up the lug strap in the form of a laminated sheet body on adrum or mandrel, such as shown at [5 in Figure 1. There is appliedaround the surface of the drum a layer of cushion stock, generallydesignated I6, of desired thickness. This cushioning body portion may beformed, of several layers of rubberized fabric such as illustrated inFigure 6. Over the resilient cushioning layer i5" is wound a-cord layerforming the strength section ll. The cord is wound on under propertension so that each strand bears its full share of the load. Ifdesired, the cord-may be wound on slightly spiral. Over the cord layerI1 is applied a rubberized fabric covering to protect the cords fromexposure. Sufficient rubberized fabric is placed under and over the cordlayer to prevent the cords from separating. Preferably, strong, toughcords which are resistant to disintegration and wear are used.

The thickness of the resilient layer It is such as to provide the propercushioning of the pick or blow and may be formed of any wear resistantresilient material. Other materials than rubber,

' such as glue, synthetic resin, or the like can be used for bonding thelayers into an integral body. Any suitable combination of strengthmaterial and binder having the required thermoiiowing 7 Figures 6, 8 and10;

ure 3, and means is provided, such as the right and left movable screwhead members 24 for expanding the core sections 25 to form the U- shapeddouble strap 22. When the core portions 25 have been expanded to aproper-amount the center member 21 is placed in position to maintain thecore sections 25 in their expanded position, as illustrated in Figure 4.Other suitable means maybe provided for expanding and maintaining thecore 2| in its outermost position. The outer surface portions of thecore sections 25 comprise an arcuate con ave surface 29 so as to providea rounded surfa e portion on the inner side of the bow or bend which istransverse tothe longitudinal axis of the lug strap.

After positioning the core on the inner side of the double lug strap 22,the core and lug strap are placed in a mold having suitablecomplementary dies 3| and 32 which are shaped to form the cavity 34 inwhich thelug strap and core are positioned for vulcanizing the strap toa hard, tough, resilient body. Suitable means, such as steam or hotwater, is circulated through the passageways 35 in order to heat themold sections 3| and 32 to the desired temperature for curing the lugstrap body 22. The mold parts 3| and 32 are shaped in such a manner asto leave a space 31 along the outer surface portion of the bend or bowof the lug strap so that the inner walls of the mold adjacent the outersurface of the lug strap at the bend do not contact the lug strappermitting proper expansion of the material during molding to equalizethe stresses in this area and. prevent the formation of wrinkles orbuckles in the laminations.

In the modification shown in Figure 5, the metal expanding core isreplaced by an air bag 39 which is expanded by fluid pressure duringmolding and .vulcanization of the double lug strap. Other suitablemethods may be employed for applying pressure to the inside of the lugstrap during molding and vulcanization.

The essential feature in the molding of the lug strap is to apply thesame pressure to the inside of the strap as to the outside so asto formalug strap free from internal stresses such as would result from theformation of wrinkles or buckles in the body portion of the strap duringshaping and molding oi the strap. For con- .veniencega double strap isformed which, after shaping, is severed in the middle formlng'twoseparate U-shaped lug straps, as illustrated in The usual slots 40 aremade in the legs of the strap before or after and setting properties maybeemployed but 1 i prefer to use rubberized fabric for this purpose. Inthis construction, the lug strap comprises a laminated body formed ofrubberized fabric built up to the desired thickness which ismolded andvulcanized to produce a U-shaped strap.

After a sleeve of sufficient width is built up on the drum o mandrel l5,one or more lug straps of the desired width are out therefrom by theapplication of a knife. or other suitable means' such as shown at 20 inFigure 2. The bands which are produced by cutting the sleevecircumferentially at spaced intervals form integral pairs of lug straps.or buckling of the body portion of the lug strap during subsequentforming and molding of the double straps, an expansible core member,generally designated 2!, is placed on the inner side of the double strapmember 22. as shown in Fig- In order to eliminate wrinkling severance ofthe double lug strap as desired. There may also be applied a cap 42,preferably made of'rubber, over'the outside of the bend or bow surfaceportion of the lug strap, as illustrated in Figures 6, 8 and 10, so asto improve the appearance of the lug strap. This gum cap, however, maybe eliminated if desired without interfering with the working propertiesof the lug strap.

In Figures 6, 8 and 10 modifications in the construction of lug strapsaccording to my invention are illustrated wherein the cushioning innersurface body of the lug strap is formed of different types of materials,such as laminated rubber fabric, Stiflex, or fabric encased rubher. Theparticular material used for forming the cushioning inner body portionof the lug strap is notimportant so long as the material is non-flowingunder the heat and humidity conditions to which the lug strap issubjected in service. When the lug strap is built up of thermoflowresistant material, such as fabrics and the like, this diillculty is notencountered. However, with the use of a predominance of thermoilowablematerial, such as heat flowable resin, rubber, and the like, it isnecessary to reduce this flow to a minimum so as to localize it to smallareas. This may be accomplished by semicuring or setting the filler tothe rubber or resin,

or encasing the same in non-fiowable material such as a fabric Jacket,similarly as shown in Figure l0.- Another method is to, load the heatflowable material with fibers oruse Stiflex. Coarse woven fabrics mayalso be used to present undue flowing of the-soft materials forming thecushion part of the lug strap.

. In the preferred embodiment of the lug strapa U-shaped body comprisingthe lug strap.

wherein the lug strap is made up of rubberized fabric layers for forming'the cushion and outer cord layer, there is produced a superior lugstrap which is free from wrinkles and buckles in the layers and has anexceptionally long life. Com-t parative test results have shown that lugstraps made according to my invention last many times longer thanconventionally constructed straps.

It is to be understood that my invention is not limited to the exactdetails of construction and the method of shaping and molding the lugstraps, since obvious modifications within the scope of this inventionmay be made by those skilled in the art.

Having thus fully described my invention, what I claim as new and desireto secure by Letters Patent is:

2. As an article of manufacture, a lug strap according to claim 1wherein the cushion layer comprises laminated rubberized fabric.

3. As an article of manufacture, a lug strap according to claim 1wherein the cushion layer comprises Stiflex.

4. As an article of manufacture, a lug strap according to claim 1wherein the cushion layer comprises rubber composition encased infabric.

. substantially thicker than said cord layer, said cushion layer andstrength layer forming, respectively, the inner and outer outline of aU- shaped body comprising the lug strap.

HENRY M. BACON.

